Seasonal fluctuations in population size and habitat segregation of Kittlitz’s Plover Charadrius pecuarius at Barberspan Bird Sanctuary, North West province, South Africa

Abstract

Seasonal fluctuations in population size reflect breeding patterns and movements of birds, but distinguishing residents from itinerant birds is difficult with partially migratory species such as Kittlitz’s Plover. We determined changes in the size of Kittlitz’s Plover populations in two microhabitats (Goose Point and Sandy Beach) at Barberspan Bird Sanctuary, North West province, South Africa, where we ringed waders between February 2008 and May 2010. Using a Bayesian model, we estimated the population of this species at these two sites from capture–recapture data gathered in eight 3- to 12-day collection periods. The estimated adult population at Goose Point peaked at 161 in October 2009, but decreased to about 40 in March 2009 and March 2010. The immature population peaked at 119 in January–February 2010. This, along with observations of nests and chicks, suggests that residents bred at Goose Point from September to March. The estimated number of adults at Sandy Beach increased from 48 in March 2010 to 380 in April 2010. Adults captured there in April 2010 formed feeding flocks and were heavier than the resident birds at Goose Point. These results suggest that Barberspan Bird Sanctuary supports resident and itinerant populations that are partially segregated in different microhabitats.

OSTRICH 2011, 82(3): 207–215